This disclosure relates to energy management, and more particularly to energy management of household consumer appliances. The disclosure finds particular application to changing existing appliances via add-on features or modules, and incorporating new energy saving features and functions into new appliances. More particularly, this disclosure relates to a method of communicating data between a master device and one or more slave devices using radio-frequency identification (RFID).
Currently utilities charge a flat rate, but with increasing cost of fuel prices and high energy usage at certain parts of the day, utilities have to buy more energy to supply customers during peak demand. Consequently, utilities are charging higher rates during peak demand. If peak demand can be lowered, then a potential huge cost savings can be achieved and the peak load that the utility has to accommodate is lessened.
One proposed third party solution is to provide a system where a controller “switches” the actual energy supply to the appliance or control unit on and off. However, there is no active control beyond the mere on/off switching. It is believed that others in the industry cease some operations in a refrigerator during on-peak time.
For example, in a refrigerator most energy is consumed to keep average freezer compartment temperature at a constant level. Recommended temperature level is based on bacteria multiplication. Normally recommended freezer temperature for long (1-2 month) food storage is 0 degrees F. Research shows that bacteria rise is a linear function of the compartment temperature, i.e., the lower the temperature the lower the bacteria multiplication. Refrigerator designers now use this knowledge to prechill a freezer compartment (and in less degree a refrigerator compartment also) before defrost, thus keeping an average temperature during time interval that includes before, during, and after defrost at approximately the same level (for example, 0 degrees F.).
There are also currently different methods used to determine when variable electricity-pricing schemes go into effect. There are phone lines, schedules, and wireless signals sent by the electrical company. One difficulty is that no peak shaving method for an appliance such as a refrigerator will provide a maximal benefit. Further, different electrical companies use different methods of communicating periods of high electrical demand to their consumers. Other electrical companies simply have rate schedules for different times of day.
Electrical utilities moving to an Advanced Metering Infrastructure (AMI) system will need to communicate to appliances, HVAC, water heaters, etc. in a home or office building. All electrical utility companies (more than 3,000 in the US) will not be using the same communication method to signal in the AMI system. Similarly, known systems do not communicate directly with the appliance using a variety of communication methods and protocols, nor is a modular and standard method created for communication devices to interface and to communicate operational modes to the main controller of the appliance. Although conventional WiFi/ZigBee/PLC communication solutions are becoming commonplace, this disclosure introduces numerous additional lower cost, reliable solutions to trigger “load shedding” responses in appliances or other users of power. This system may also utilize the commonplace solutions as parts of the communication protocols.